The proposed project examines in detail the presentation, differential diagnosis and treatment response of depression in Alzheimer's disease; the impact of treatment of life quality factors; and relationship between depression and cognitive function. The specific aims are to (1) study the effect of antidepressant intervention upon life quality factors and cognition in depressed Alzheimer's patients, and (2) compare these study patients to 60 age-sex matched nondemented depressives and 60 age-sex matched normal controls. Sixty consenting patients 55 years or older who are eligible for this project will be assessed with a modified version of the Structural Clinical Interview for DSM-III-R-Depression (SCID - Depression) incorporating the Hamilton Depression Rating Scale (HAM-D), Brief Psychiatric Rating Scale (BPRS) and Clinicians Global impression Scale (CGI). The HAM-D, BPRS and CGI will be administered at each visit throughout treatment. In addition to these measures and other laboratory, biomedical examinations and neuropsychological measures employed within the Core of the proposed Alzheimer's Program Project, subjects entering this project will undergo baseline assessments with the Alzheimer's Disease Assessment Scale (ADAS), the MIni-Mental State Examination (MMSE) Instrumental Activities of Daily Living Scale (IADL), Physical Self- Maintenance Scale, and Psychosocial Adjustment to Illness Scale (PAIS). These measures of life quality and cognition will be repeated at 3, 6, 12, and 18 months. In order to assess the significance of antidepressant intervention in relation to the above measures of life quality and cognition, data analysis will be carried out using a repeated measures ANOVA, using the 5% level of significance which is predicted to allow a statistical power of 80%. This project has substantial merit in demonstrating the impact of antidepressant treatment in Alzheimer's dementia relative to life quality factors and further clarifying the relationship between mood and cognition.